<meta property="og:title" content="{% if page.title %}{{ page.title }}{% else %}{{ site.title }}{% endif %}" />
<meta property="og:type" content="website" />
<meta property="og:url" content="{{ site.url }}/{{ site.baseurl }}/{{ page.url }}" />
<meta property="og:image" content="{{ site.url }}/{{ site.baseurl }}/{% if page.header-img %}{{ page.header-img }}{% else %}{{ site.header-img }}{% endif %}">